textproduct: Albany

WHAT HAS CHANGED

Continued trend of lowering daytime high temps from the NBM through Wednesday, with the greatest adjustments today. Forecast for tonight into tomorrow morning continues to trend wetter, with increasing confidence for widespread rain/showers across the region. Given this wetter trend, have added mention of isolated ponding of water in the typical low-lying and/or poor drainage areas tonight into tomorrow morning.

KEY MESSAGES

1) Periods of rain expected through Monday morning, albeit with a brief break late this afternoon through this evening. While flooding concerns remain low, some nuisance ponding of water in poor drainage and/or low-lying areas will be possible tonight into tomorrow morning.

2) Temperatures trend warmer Tuesday and Wednesday with a chance for showers and a few thunderstorms for the middle to end of the week.

DISCUSSION

KEY MESSAGE 1...As of 2:05 AM EDT...Current sfc analysis shows an inverted trough associated with a decaying primary low over western NY, with a secondary inverted trough along the NJ coastline. Radar shows that most of the shower activity at this time is associated with these features, as well as across our N/NE zones with a band of 700 mb FGEN that will continue tracking north and east over the next few hours. However, as we head through the rest of the night into this morning, a warm front will approach from the south. CIRA ALPW satellite imagery shows low-level moisture feed into/just south of the region from the Atlantic associated with 30-40 kt southeasterly LLJ, with an additional Gulf moisture connection in the 700-500 mb layer with deep S/SW flow aloft. While the sfc front remains south of our area today, strengthening mid-level warm advection and isentropic lift on the 285 and 290 K theta surfaces overlapping with this deep moisture will result in redevelopment of rain/showers as we head towards daybreak. Rain persists through most of the day before tapering off late this afternoon into the evening from west to east. Today will remain quite cool, with highs in the 40s (terrain) to low 50s (valleys). We once again collaborated with neighboring WFOs to lower NBM temps by several degrees for today.

The forecast for tonight into tomorrow has trended quite a bit wetter from previous forecasts. Northern and southern stream shortwave features phase to our west, becoming negatively tilted over the Ohio Valley and Great Lakes tonight. While there was previously some uncertainty in the degree of phasing between these features, the less impressive CMC/Euro have caved to the more robust NAM and GFS with the northern feature digging further south and the southern stream feature looking stronger than previously modeled. As the warm front finally lifts north tonight, moisture continues to increase, with PWATs climbing to 1.5-1.7", which is near the daily max at ALY per the SPC sounding climatology. The overlap of upper forcing and anomalous moisture will lead to another round of widespread rain tonight. Guidance also suggests that there could be a few pockets of elevated instability, so a few rumbles of thunder will be possible. Rain comes to and end from west to east Monday morning as a cold front sweeps through the region. While the morning looks wet for at least our western New England areas, we should see much drier weather for Monday afternoon with some breaks of sun and temperatures climbing into the 70s.

Between the rain that falls today and the rain tonight into tomorrow morning, an additional half inch to inch plus of rain is expected, with the highest amounts in the southern ADKs. While these rainfall amounts have increased from the previous forecast due to the wetter trend tonight into Monday, these rainfall amounts still look too low for any river flood issues. However, for tonight into tomorrow morning, there may be some embedded heavier rainfall rates (00z HREF is showing 10% chance for 1" of rain in 3 hrs) that could result in a few instances of nuisance ponding of water in low-lying and poor drainage areas. The best chance appears to be over northern areas where low-level convergence is strongest, and will be enhanced by upsloping into the southern ADKs. Fortunately, the elevated instability looks to remain mainly across our southern areas, so the lack of overlap between the best forcing and instability should prevent more widespread or more serious hydro concerns.

KEY MESSAGE 2...Tuesday looks dry and warmer with flow becoming zonal aloft and sfc high pressure building overhead. Highs will be in the 70s (terrain) to low 80s (valleys). We again collaborated with neighboring WFOs to knock down NBM temps a few degrees due to it noticeable warm bias. Wednesday, flow aloft becomes more northwesterly as upper ridging amplifies over the center of the country. Temperatures will remain above normal, and will be within a couple degrees of Tuesday's highs. While the timing remains somewhat uncertain, there continues to be decent agreement from guidance for an upper shortwave and associated cold front to dive southeastward across our region at some point Wednesday or Wednesday night. If the timing of the cold front and upper forcing align with daytime heating, then showers and thunderstorms will be possible, and even a few stronger storms can't be ruled out. However, if the timing is later Wednesday night then there may not be much in the way of precip or storms at all. Behind the cold front, temperatures are expected to be several degrees cooler, closer to seasonal normals. While we will be on the downstream side of an omega block with dry N/NW flow through the end of the week, additional upper shortwaves diving south from Canada may lead to isolated showers at times, although confidence in timing and coverage is very low this far out.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

A steady light rain has spread across much of the region and this will continue through the early to mid afternoon hours. Although flying conditions will have been VFR for much of the overnight hours, with steady rainfall now occurring, ceilings will generally be MVFR for the morning hours, with ceilings in the 1500-2500 ft range. While visibility will generally be 6SM or so in rain showers, it may briefly lower to 3-5SM within some bursts. Cannot totally rule out brief periods of IFR as well for ceilings lowering to 800-1000 ft at times as well, mainly for KPOU and KPSF.

The steady rainfall will be tapering off in the early to mid afternoon hours for all sites. Still, flying conditions will remain MVFR, as lingering low level moisture keeps ceilings around 1500-2500 ft for the rest of the day today and into the evening hours. Another round of steadier showers looks to return again for late tonight, with continued MVFR ceilings and periods of MVFR visibility. IFR ceilings cannot be ruled out late tonight as well.

Light easterly winds around 5 kts are currently in place. They will eventually become 5-10 kts, mainly still from the east to southeast for much of the day. Winds will continue to be east to northeast for this evening into tonight but will be rather light, mainly around 5 kts or less.

Outlook...

Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SHRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.